Also known as A-2 stainless, 18-8 is the most common grade of stainless steel for general use.
Zinc plated for moderate corrosion resistance. A tempered medium carbon steel. Class 8.8 is hardened, but it is not as strong as class 10.9. It is commonly found in automotive applications. Class 8.8 is similar to grade 5.
For adding a machine thread to material that otherwise cannot be tapped.